2. Electric potential and capacitance — Physics STD 12 Science — Question

$(a)$ The electric lines of force entering into a Gaussian surface provide negative flux.

$(b)$ A charge ' $q$ ' is placed at the centre of a cube. The flux through all the faces will be the same.

$(c)$ In a uniform electric field net flux through a closed Gaussian surface containing no net charge, is zero.

$(d)$ When electric field is parallel to a Gaussian surface, it provides a finite non-zero flux.

Choose the most appropriate answer from the options given below

$(1)$ If $h >2 R$ and $r > R$ then $\Phi=\frac{ Q }{\in_0}$

$(2)$ If $h <\frac{8 R }{5}$ and $r =\frac{3 R }{5}$ then $\Phi=0$

$(3)$ If $h >2 R$ and $r =\frac{4 K }{5}$ then $\Phi=\frac{ Q }{5 \in_0}$

$(4)$ If $h >2 R$ and $r =\frac{3 K }{5}$ then $\Phi=\frac{ Q }{5 \in_0}$